Facebook questions / 1. Air Bubbles - 2. Repair vs Replace

I received 2 questions on our facebook page last week and hope to continue the trend from week to week. If you have a question about windshields, auto glass, or even just the auto industry, post it on our facebook page and I will have an answer for you as quickly as possible.

Question 1 submitted by Henry P.
I noticed on mothers cadillac at the top of the front windshield some tiny bubbles within 1/8" of the edge at the top - what's up? It's the factory glass.

Henry, do not worry. This is not an uncommon phenomenon in windshields. That is not to say that it is very common, but for now these bubbles are not dangerous. To explain exactly what these are, let me touch on the components of a windshield. A windshield is made up of three parts - 2 sheets of glass with 1 layer of plastic in between. All 3 parts are then put into an oven where both heat and pressure are applied in a process called lamination. This process is essential because lamination is what allows your windshield to crack upon impact rather than shatter.

The tiny bubbles that you are seeing, Henry, are simply air bubbles. They are a direct result of the lamination process, but a couple of things could have occurred. One, there may not have been enough pressure on that portion of the glass during lamination...and two, that area of the windshield may not have heated properly resulting in a tiny section of plastic that is not completely melted.

Regardless of the cause, the bubbles are just an eye sore for right now. However, if a rock were to hit the windshield in that area, the air bubbles could easily cause what would normally be a small chip to be a running crack. It isn't likely, but it is possible. And, once again, it isn't uncommon. I returned a windshield one day last week that had around 15 air bubbles in it. Quality control can't catch them all. See my link at the end for more information on how a windshield is made.

Question 2 submitted by Nicole C.

If I have a crack in my windshield, can you just repair it or do you have to replace the entire windshield?

Nicole, the simple answer is it depends on how the crack has spread. If it is a simple rock chip, it can probably be repaired. If it is a crack that is any longer than 4 inches (the size of a credit card), Kittrell Glass will only replace your windshield rather than repair it. This is because trying to stop a crack that has already spread is nearly impossible. It can be done and there are those that will attempt it all day long. However, we feel it a great disservice to attempt a nearly impossible windshield repair only to result in a longer crack or a crack that ends up spreading again in 3 months.

Another thing to consider when it comes to repair is your cost savings. A repair can run anywhere from $50-$100 at Kittrell Glass. There are several companies in Birmingham that are charging $100-$150 per repair. When the average windshield replacement costs $215, how much are you really saving with a repair?

Also, keep in mind that there is a possibility with every single repair that the minor chip or crack can quickly shoot to 8 inches in the blink of an eye. There is approximately a 1 in 10 chance of this happening, so be prepared to replace your windshield even if you are just getting a simple repair. Follow the link below for pictures of damage that can most likely be repaired.

Relevant Links

How a windshield is made

Repairable damage

Your windshield and how it protects you

Most people do not realize that the windshield has another function other than to keep the cool wind out of their face while driving down the road. It isn't their fault that they believe this and I can't really blame them. No one has taken the time nor seen a reason to educate consumers on the importance of their windshield. If you continue reading, you will more than likely think twice about having just anyone replace your windshield when the time comes.

Your Windshield's Purpose
First of all, your windshield is designed to protect. From everyday driving to a life-threatening wreck, your windshield is protecting you and your family at all times. Your windshield is also a key component to your car's supplemental restraint system (SRS) or airbag. If it were not for your windshield, the passenger's side airbag would be completely useless. This is because the passenger's airbag uses the windshield as a backstop to ensure that it is deployed in the correct position. Think about it...the driver's airbag is in the steering wheel and inflates toward the driver. However, the passenger's airbag is on top of the dash and inflates upward and away from the passenger. Because the windshield is curved, the passenger's airbag is able to inflate upward and then follow the curvature of the windshield toward the passenger...granted that the windshield is properly installed.

There are many, many "time-saving" techniques that some installers use to replace a windshield as quickly as possible, but they almost always result in an improper installation. I will write about the dangers of an improper installation soon; but, in short, an improper installation or replacement can result in the passenger's airbag not deploying correctly thus being useless.

The windshield also protects the driver and passenger from being ejected during a collision as well. This is fairly obvious, but it takes a lot of prep work and attention to detail to ensure that the windshield has the strongest bond possible to prevent it from detaching during a collision.

One of the lesser known functions of a windshield is to absorb impact. When we think of glass, we don't exactly think of soft. However, windshields have three layers - two layers of glass with a layer of polyvinyl in between. This prevents the windshield from shatterning upon any impact as well as creates elasticity. Even though the outside layer of glass may chip or crack, the inside layer allows the windshield to remain flexible and absorb any impact that may occur.

Finally, your windshield provides a substantial amount of support for your roof. Would you be shocked to know that your windshield is supporting up to 60% of your car's roof? Well, shocked or not, it is true and you should be very thankful. Car manufacturers have spent large amounts of time on roof support. This is because a roof collapsing on a passenger has the highest percentage of fatality. But wait...the windshield is there to protect you! As I said earlier, the windshield supports up to 60% of weight placed on your roof.

So, hopefully you have read through this information and understand a little more about the importance of your windshield. If you already knew some of this, congratulations. I hope you will educate the others around you.

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